What Is ASTM A53?

Quick Answer

ASTM A53 covers black and hot-dipped galvanized welded (Type E, ERW) and seamless (Type S) carbon steel pipe in NPS 1/8 to NPS 26. Grade B (minimum yield 240 MPa) is the most common grade, used for mechanical, pressure, and general-purpose applications.

ASTM A53 is one of the most versatile pipe specifications in the industry. It covers both manufacturing methods (welded and seamless), includes galvanizing options, and applies to various services from steam and water conveyance to structural and fire protection systems.

Types and Grades

Designation	Manufacturing	Grade A YS (min)	Grade A TS (min)	Grade B YS (min)	Grade B TS (min)
Type F	Furnace butt-welded (continuous)	172 MPa (25 ksi)	330 MPa (48 ksi)	N/A	N/A
Type E	Electric resistance welded (ERW)	205 MPa (30 ksi)	330 MPa (48 ksi)	240 MPa (35 ksi)	415 MPa (60 ksi)
Type S	Seamless	205 MPa (30 ksi)	330 MPa (48 ksi)	240 MPa (35 ksi)	415 MPa (60 ksi)

Type F (furnace-welded) is largely obsolete. The market focuses on Type E and Type S.

Chemical Composition

Element	Type E, Grade B	Type S, Grade B
Carbon (max)	0.30%	0.30%
Manganese (max)	1.20%	1.20%
Phosphorus (max)	0.035%	0.035%
Sulfur (max)	0.035%	0.035%
Silicon (min)	0.10%	0.10%
Copper (max)	0.40%	0.40%
Nickel (max)	0.40%	0.40%
Chromium (max)	0.40%	0.40%
Molybdenum (max)	0.15%	0.15%
Vanadium (max)	0.08%	0.08%

Weld Joint Factor

Under ASME B31.3, the weld joint efficiency factor (E) for ASTM A53 pipe is:

• Type S (seamless): E = 1.0
• Type E (ERW): E = 0.85

This means ERW pipe requires 15% more wall thickness than seamless to achieve the same allowable pressure, unless the weld seam is 100% examined (raising E to 1.0 per code provisions).

Applications

• Steam, water, air, and gas distribution lines
• Fire protection sprinkler systems (often galvanized)
• Structural members (fencing, bollards, handrails)
• Mechanical and general-purpose pressure applications
• Oil field use (ASTM A53 Type S is often dual-certified with ASTM A106 Grade B)

Galvanizing

ASTM A53 includes provisions for hot-dip galvanizing per ASTM A123. Galvanized pipe is standard for water supply, fire protection, and exposed outdoor piping where corrosion protection is needed without external coating.

Pro Tip

ASTM A53 Type E Grade B with galvanizing is the go-to specification for fire protection systems. Verify that the galvanizing meets ASTM A123 and that threaded connections use A53 Type E or Type S (not Type F).

For a comparison with ASTM A106, see ASTM A106 vs A53.

Read the full guide to pipe types